commit b5b4aa62c124cf5c6c8d7a520137acbc0f3dc525
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Fri Apr 9 10:02:30 2021 -0300

    libsupport: Add support_select_modifies_timeout
    
    It will be used on a select() test.
    
    (cherry picked from commit 5628f103f5937611730845390928cb43ef716012)

diff --git a/support/Makefile b/support/Makefile
index bb9889efb4be3630..4fd76b0e5e4add3f 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -67,6 +67,7 @@ libsupport-routines = \
   support_quote_string \
   support_record_failure \
   support_run_diff \
+  support_select_modifies_timeout \
   support_set_small_thread_stack_size \
   support_shared_allocate \
   support_small_stack_thread_attribute \
diff --git a/support/support.h b/support/support.h
index 9cbc45572054fd90..9c9612644a70e46f 100644
--- a/support/support.h
+++ b/support/support.h
@@ -23,6 +23,7 @@
 #ifndef SUPPORT_H
 #define SUPPORT_H
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <sys/cdefs.h>
 /* For mode_t.  */
@@ -129,6 +130,10 @@ extern void support_copy_file (const char *from, const char *to);
 extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
 					size_t, unsigned int);
 
+/* Return true if select modify the timeout to reflect the amount of time
+   no slept.  */
+extern bool support_select_modifies_timeout (void);
+
 __END_DECLS
 
 #endif /* SUPPORT_H */
diff --git a/support/support_select_modifies_timeout.c b/support/support_select_modifies_timeout.c
new file mode 100644
index 0000000000000000..653ea2cc9850b005
--- /dev/null
+++ b/support/support_select_modifies_timeout.c
@@ -0,0 +1,29 @@
+/* Return whether select modifies the timeout.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/support.h>
+
+bool
+support_select_modifies_timeout (void)
+{
+#ifdef __linux__
+  return true;
+#else
+  return false;
+#endif
+}